net/mlx5e: Update hw flows when encap source mac changed

When we offload tc filters to hardware, hardware flows can
be updated when mac of encap destination ip is changed.
But we ignore one case, that the mac of local encap ip can
be changed too, so we should also update them.

To fix it, add route_dev in mlx5e_encap_entry struct to save
the local encap netdevice, and when mac changed, kernel will
flush all the neighbour on the netdevice and send NETEVENT_NEIGH_UPDATE
event. The mlx5 driver will delete the flows and add them when neighbour
available again.

Fixes: 232c001 ("net/mlx5e: Add support to neighbour update flow")
Cc: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c

@@ -256,6 +256,7 @@ int mlx5e_tc_tun_create_header_ipv4(struct mlx5e_priv *priv,
 	e->m_neigh.family = n->ops->family;
 	memcpy(&e->m_neigh.dst_ip, n->primary_key, n->tbl->key_len);
 	e->out_dev = out_dev;
+	e->route_dev = route_dev;
 
 	/* It's important to add the neigh to the hash table before checking
 	 * the neigh validity state. So if we'll get a notification, in case the
@@ -369,6 +370,7 @@ int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
 	e->m_neigh.family = n->ops->family;
 	memcpy(&e->m_neigh.dst_ip, n->primary_key, n->tbl->key_len);
 	e->out_dev = out_dev;
+	e->route_dev = route_dev;
 
 	/* It's importent to add the neigh to the hash table before checking
 	 * the neigh validity state. So if we'll get a notification, in case the

drivers/net/ethernet/mellanox/mlx5/core/en_rep.c

@@ -596,6 +596,10 @@ static void mlx5e_rep_update_flows(struct mlx5e_priv *priv,
 	if (neigh_connected && !(e->flags & MLX5_ENCAP_ENTRY_VALID)) {
 		ether_addr_copy(e->h_dest, ha);
 		ether_addr_copy(eth->h_dest, ha);
+		/* Update the encap source mac, in case that we delete
+		 * the flows when encap source mac changed.
+		 */
+		ether_addr_copy(eth->h_source, e->route_dev->dev_addr);
 
 		mlx5e_tc_encap_flows_add(priv, e);
 	}

drivers/net/ethernet/mellanox/mlx5/core/en_rep.h

@@ -148,6 +148,7 @@ struct mlx5e_encap_entry {
 	unsigned char h_dest[ETH_ALEN];	/* destination eth addr	*/
 
 	struct net_device *out_dev;
+	struct net_device *route_dev;
 	int tunnel_type;
 	int tunnel_hlen;
 	int reformat_type;